PageCache

API reference › yii › filters › PageCache

class	`yii\filters\PageCache`
Extends	`yii\base\ActionFilter` » `yii\base\Behavior` » `yii\base\BaseObject`
Implements	`yii\base\DynamicContentAwareInterface`, `yii\base\Configurable`
Uses traits	`yii\base\DynamicContentAwareTrait`
Since	2.0
Source	`framework/filters/PageCache.php`

PageCache implements server-side caching of whole pages.

It is an action filter that can be added to a controller and handles the beforeAction event.

To use PageCache, declare it in the behaviors() method of your controller class. In the following example the filter will be applied to the index action and cache the whole page for maximum 60 seconds or until the count of entries in the post table changes. It also stores different versions of the page depending on the application language.

public function behaviors()
{
    return [
        'pageCache' => [
            'class' => 'yii\filters\PageCache',
            'only' => ['index'],
            'duration' => 60,
            'dependency' => [
                'class' => 'yii\caching\DbDependency',
                'sql' => 'SELECT COUNT(*) FROM post',
            ],
            'variations' => [
                \Yii::$app->language,
            ]
        ],
    ];
}

Properties

Property	Type	Description	Defined by
`$cache`	`yii\caching\CacheInterface\|array\|string`	The cache object or the application component ID of the cache object. Default: `'cache'`.	`PageCache`
`$cacheCookies`	`bool\|array`	A boolean value indicating whether to cache all cookies, or an array of cookie names indicating which cookies can be cached. Default: `false`. Available since 2.0.4.	`PageCache`
`$cacheHeaders`	`bool\|array`	A boolean value indicating whether to cache all HTTP headers, or an array of HTTP header names (case-sensitive) indicating which HTTP headers can be cached. Default: `true`. Available since 2.0.4.	`PageCache`
`$dependency`	`array\|yii\caching\Dependency`	The dependency that the cached content depends on. Default: `null`.	`PageCache`
`$duration`	`int`	Number of seconds that the data can remain valid in cache. Default: `60`.	`PageCache`
`$dynamicPlaceholders`	`array`	A list of placeholders.	`yii\base\DynamicContentAwareTrait`
`$enabled`	`bool`	Whether to enable the page cache. Default: `true`.	`PageCache`
`$except`	`array`	List of action IDs that this filter should not apply to. Default: `[]`.	`yii\base\ActionFilter`
`$only`	`array`	List of action IDs that this filter should apply to. Default: `[]`.	`yii\base\ActionFilter`
`$owner`	`yii\base\T\|null`	The owner of this behavior Default: `null`.	`yii\base\Behavior`
`$variations`	`string[]\|string\|callable`	List of factors that would cause the variation of the content being cached. Default: `null`.	`PageCache`
`$varyByRoute`	`bool`	Whether the content being cached should be differentiated according to the route. Default: `true`.	`PageCache`
`$view`	`yii\base\View\|null`	The view component to use for caching. Default: `null`.	`PageCache`

Methods

Method	Description	Defined by
`__construct()`	Constructor.	`yii\base\BaseObject`
`__call()`	Calls the named method which is not a class method.	`yii\base\BaseObject`
`__get()`	Returns the value of an object property.	`yii\base\BaseObject`
`__isset()`	Checks if a property is set, i.e. defined and not null.	`yii\base\BaseObject`
`__set()`	Sets value of an object property.	`yii\base\BaseObject`
`__unset()`	Sets an object property to null.	`yii\base\BaseObject`
`addDynamicPlaceholder()`	Adds a placeholder for dynamic content.	`yii\base\DynamicContentAwareTrait`
`afterAction()`	This method is invoked right after an action is executed.	`yii\base\ActionFilter`
`afterFilter()`		`yii\base\ActionFilter`
`afterRestoreResponse()`	This method is invoked right after the response restoring is finished (but before the response is sent).	`PageCache`
`attach()`	Attaches the behavior object to the component.	`yii\base\ActionFilter`
`beforeAction()`	This method is invoked right before an action is to be executed (after all possible filters.) You may override this method to do last-minute preparation for the action.	`PageCache`
`beforeCacheResponse()`	This method is invoked right before the response caching is to be started.	`PageCache`
`beforeFilter()`		`yii\base\ActionFilter`
`cacheResponse()`	Caches response properties.	`PageCache`
`canGetProperty()`	Returns a value indicating whether a property can be read.	`yii\base\BaseObject`
`canSetProperty()`	Returns a value indicating whether a property can be set.	`yii\base\BaseObject`
`className()` static	Returns the fully qualified name of this class.	`yii\base\BaseObject`
`detach()`	Detaches the behavior object from the component.	`yii\base\ActionFilter`
`events()`	Declares event handlers for the `$owner`’s events.	`yii\base\Behavior`
`getDynamicPlaceholders()`	Returns a list of placeholders for dynamic content. This method is used internally to implement the content caching feature.	`yii\base\DynamicContentAwareTrait`
`getView()`		`PageCache`
`hasMethod()`	Returns a value indicating whether a method is defined.	`yii\base\BaseObject`
`hasProperty()`	Returns a value indicating whether a property is defined.	`yii\base\BaseObject`
`init()`	Initializes the object.	`PageCache`
`setDynamicPlaceholders()`	Sets a list of placeholders for dynamic content. This method is used internally to implement the content caching feature.	`yii\base\DynamicContentAwareTrait`
`calculateCacheKey()` protected		`PageCache`
`getActionId()` protected	Returns an action ID by converting `Action::$uniqueId` into an ID relative to the module.	`yii\base\ActionFilter`
`isActive()` protected	Returns a value indicating whether the filter is active for the given action.	`yii\base\ActionFilter`
`restoreResponse()` protected	Restores response properties from the given data.	`PageCache`
`updateDynamicContent()` protected	Replaces placeholders in $content with results of evaluated dynamic statements.	`yii\base\DynamicContentAwareTrait`

Constants

Constant	Value	Description	Defined by
`PAGE_CACHE_VERSION`	`1`	Page cache version, to detect incompatibilities in cached values when the data format of the cache changes.	`PageCache`

Property details

$cache

public yii\caching\CacheInterface|array|string $cache = 'cache'

The cache object or the application component ID of the cache object.

After the PageCache object is created, if you want to change this property, you should only assign it with a cache object. Starting from version 2.0.2, this can also be a configuration array for creating the object.

$cacheCookies

public bool|array $cacheCookies = false

A boolean value indicating whether to cache all cookies, or an array of cookie names indicating which cookies can be cached.

Be very careful with caching cookies, because it may leak sensitive or private data stored in cookies to unwanted users.

Since

2.0.4

$cacheHeaders

public bool|array $cacheHeaders = true

A boolean value indicating whether to cache all HTTP headers, or an array of HTTP header names (case-sensitive) indicating which HTTP headers can be cached.

Note if your HTTP headers contain sensitive information, you should white-list which headers can be cached.

Since

2.0.4

$dependency

public array|yii\caching\Dependency $dependency = null

The dependency that the cached content depends on.

This can be either a Dependency object or a configuration array for creating the dependency object. For example,

[
    'class' => 'yii\caching\DbDependency',
    'sql' => 'SELECT MAX(updated_at) FROM post',
]

would make the output cache depend on the last modified time of all posts. If any post has its modification time changed, the cached content would be invalidated.

If $cacheCookies or $cacheHeaders is enabled, then Dependency::$reusable should be enabled as well to save performance. This is because the cookies and headers are currently stored separately from the actual page content, causing the dependency to be evaluated twice.

$duration

public int $duration = 60

Number of seconds that the data can remain valid in cache.

Use 0 to indicate that the cached data will never expire.

$enabled

public bool $enabled = true

Whether to enable the page cache.

You may use this property to turn on and off the page cache according to specific setting (e.g. enable page cache only for GET requests).

$variations

public string[]|string|callable $variations = null

List of factors that would cause the variation of the content being cached.

Each factor is a string representing a variation (e.g. the language, a GET parameter). The following variation setting will cause the content to be cached in different versions according to the current application language:

[
    Yii::$app->language,
]

Since version 2.0.48 you can provide an anonymous function to generate variations. This is especially helpful when you need to access the User component, which is resolved before the PageCache behavior:

'variations' => function() {
    return [
        Yii::$app->language,
        Yii::$app->user->id
    ];
}

The callable should return an array.

$varyByRoute

public bool $varyByRoute = true

Whether the content being cached should be differentiated according to the route.

A route consists of the requested controller ID and action ID. Defaults to true.

$view

public yii\base\View|null $view = null

The view component to use for caching.

If not set, the default application view component Application::$view will be used.

Method details

afterRestoreResponse()

public function afterRestoreResponse(array|null $data): mixed

This method is invoked right after the response restoring is finished (but before the response is sent).

You may override this method to do last-minute preparation before the response is sent.

Parameters

Parameter	Type	Description
`$data`	`array\|null`	An array of an additional data stored in a cache entry or `null`.

Returns

mixed

Since

2.0.11

beforeAction()

public function beforeAction(mixed $action): bool

This method is invoked right before an action is to be executed (after all possible filters.) You may override this method to do last-minute preparation for the action.

Parameters

Parameter	Type	Description
`$action`	`mixed`	The action to be executed.

Returns

bool: Whether the action should continue to be executed.

beforeCacheResponse()

public function beforeCacheResponse(): bool|array

This method is invoked right before the response caching is to be started.

You may override this method to cancel caching by returning false or store an additional data in a cache entry by returning an array instead of true.

Returns

bool|array: Whether to cache or not, return an array instead of true to store an additional data.

Since

2.0.11

cacheResponse()

public function cacheResponse(): mixed

Caches response properties.

Returns

mixed

Since

2.0.3

getView()

public function getView()

init()

public function init(): mixed

Initializes the object.

This method is invoked at the end of the constructor after the object is initialized with the given configuration.

Returns

mixed

calculateCacheKey()

protected function calculateCacheKey(): array

Returns

array: The key used to cache response properties.

Since

2.0.3

restoreResponse()

protected function restoreResponse(yii\web\Response $response, array $data): mixed

Restores response properties from the given data.

Parameters

Parameter	Type	Description
`$response`	`yii\web\Response`	The response to be restored.
`$data`	`array`	The response property data.

Returns

mixed

Since

2.0.3